When studying Luke 15 and the three parables Jesus tells to the Non-rejoicing Pharisees and Scribes about the lost coming home, I did a little thought experiment.
First, the parable of the Prodigal Son is one of repentance and turning from sin, it's about sonship and coming to a full awareness of what that means in Christ, but it is centrally about the welcoming of the lost back home. The shepherd throws a party for the recovered sheep and the woman rejoices with her neighbors over the recovered coin. Just so, it is the Father that properly received the lost son with his audacious generosity. This is a show of Christian hospitality and welcoming to the sinner, the outsider and the lost.
As Fr. Henri Nouwen recounts in his book on the Prodigal Son, a woman tells him that he may at times see himself as the younger brother, a wayward sinner, or as the elder brother, a self-righteous moralist, but God is calling you to be the father. That's it for us. Jesus tells this made up story to get the Pharisees and Scribes to have the correct attitude towards sinners. We should be like the father of the story and rejoice that the lost are found, that the dead are alive again.
Meditating on this, combined with my own experiences of a lack of Catholic hospitality to the broken and sinful, I began to realize that in many Churches when the sinner returns to Mass he or she often encounters not the father, but the elder brother.
What would happen if the elder brother was working in the fields by the road to the house instead of farther away and was the one that caught sight of him?